*1.1.1. Otariid and phocid species of Uruguay*

Uruguay has 450 km of shorelines along the La Plata River and 220 km along the Atlantic Ocean (MTOP-PNUD-UNESCO, 1980). Two species of Otariids breed and reproduce on Uruguayan Atlantic islands: the South American fur seal, *Arctocephalus australis* (Zimmermann, 1783) (Fig. 1), and the South American sea lion, *Otaria flavescens* (Shaw, 1800), (Fig. 2), (Ponce de León, 2000; Ponce de León & Pin 2006; Vaz-Ferreira, 1976, 1982). Both are polygynous, gregarious and show strong sexual dimorphism (Bartholomew, 1970). South American fur seal adult males reach lengths of 1.9 m and weigh from 120 kg to 200 kg, while females can reach 1.4 m long and weigh from 40 kg to 55 kg, and newborns can be from 0.4 m to 0.5 m long and weigh from 3.5 kg to 5.5 kg (Vaz-Ferreira, 1982). Sea lion males may reach 2.8 m and weigh up to 354 kg while adult females are much smaller, reaching up to 1.9 m long and weighing as much as 150.0 kg (Ponce de León, 2000). Newborns in this species are between 0.7 m and 0.9 m long and weigh from 10.0 kg to 17.0 kg (Cappozzo et al., 1994). A third pinniped species, the southern elephant seal *Mirounga leonina* (Fig. 3), is a frequent visitor of Uruguayan islands and shorelines, although its reproductive areas are located in Argentina. Elephant seals can reach up to 5 m, 3 m or 1.3 m in length for males, females and pups respectively, and they can weigh as much as 5,000 kg, 800 kg from 40 kg to 50 kg (Reeves et al., 1992).

© 2012 Arbiza et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Uruguayan Pinnipeds (*Arctocephalus australis* and *Otaria flavescens*): Evidence of Influenza Virus and *Mycobacterium pinnipedii* Infections 153

**Figure 3.** Young male southern elephant seal *Mirounga leonina* on Coronilla's Islet. Photograph: A.

The exploitation of fur seals by Europeans in Uruguay is known to have begun in 1516, soon after the Spaniards explored the South Western Atlantic Ocean. During this exploration, Juan Díaz de Solís discovered the La Plata River and his crew landed on Isla de Lobos, where they killed 66 seals for their meat to be salted and consumed on their way back to Europe. The first semi-organized commercial exploitation took place in 1724, and the seal oil obtained was used for illuminating the city of Maldonado. From 1792 the Real Compañía Marítima, under direct instructions of the King of Spain, was responsible for sealing, until England invaded the territory in 1808. Shortly after, seal harvesting was carried out by private concessionaries and controlled by the local Government. From 1873 to 1900 a total of 440,000 seals were slaughtered (annual average of 16,000 pelts), whereas no records are available from 1901 to 1909. Further on, from 1910 to 1942, 72,000 South American fur seals were killed, as well as 17,000 more between 1943 and 1947. Due to the uncontrolled exploitation, populations of both seal species began to decrease. After 1950 a new management scheme started on Isla de Lobos, based on the system used for Northern fur seals (*Callorhinus ursinus*) in Pribilof Islands (Alaska), and the harvest was restricted to males. Also, private sector concessions were suspended, and the Government directly organized the harvesting program and related activities. Between 1959 and 1991 a total of 276,000 South American fur seals were removed (about 8,400 animals per year) and from 1967 to 1978, 36,400 sea lions were also slaughtered (3,000 animals per year). Products taken were crude skins, oil, meat and male genitals. Pelts were tanned and prepared in specific areas in Uruguay. Carcasses and fat were processed to obtain special oil for making soap, cosmetics and paints. In the XIX century, seal oil was used for illuminating the main streets of some cities. The meat was sometimes dried and given to the Montevideo Zoo for feeding big cats, eagles and condors. Since 1980, genitals were processed and sold for preparing

Ponce de León.

**1.2. Brief exploitation history** 

**Figure 1.** Group of South American fur seal *Arctocephalus australis* males, females and pups on Lobos Island. Photograph: A. Ponce de León.

**Figure 2.** South American sea lion *Otaria flavescens* reproductive groups with pups on Marco Island with pups. Photograph: A. Ponce de León.

**Figure 3.** Young male southern elephant seal *Mirounga leonina* on Coronilla's Islet. Photograph: A. Ponce de León.
